1. Field of the Invention
The present invention relates to a muffler (e.g., a silencer) mounted to a vehicle, and more particularly to an optimized structure for an integrated catalytic muffler, in which a selective catalytic reduction (SCR) catalytic unit is integrally coupled to a muffler by bolting or clamping to insert a portion of the SCR catalytic unit into the muffler and expose the remaining portion out of the muffler, thereby substantially reducing the production cost and weight and facilitating maintenance and repair.
2. Description of the Related Art
In general, an exhaust system is mounted on the underbody of a vehicle to reduce noise and remove impurities from exhaust gas generated from an engine before the exhaust gas is emitted to the atmosphere. An exhaust system typically includes an exhaust manifold connected with a cylinder head of an engine, one or more mufflers configured to reduce noise by applying resistance to the flow of the exhaust gas from the engine, and a catalytic converter (a catalytic unit) configured to convert toxic substances, such as hydrocarbons, carbon monoxide, nitrogen oxides, etc., included in the exhaust gas into carbon dioxide, water, nitrogen, oxygen, etc., which are harmless to humans, through oxidation-reduction reactions.
The exhaust manifold, the muffler, and the catalytic converter communicate with each other via exhaust pipes, and a tail pipe, which communicates with the exterior, is coupled to the distal end of the muffler. The muffler is configured to reduce noise generated from exhaust gas by decreasing the temperature and the pressure of the exhaust gas. Recently, a muffler having a built-in catalytic converter (i.e. a muffler in which a catalytic converter is embedded) is being widely used to efficiently utilize the space for mounting the exhaust system and simplify the layout thereof. The muffler having the built-in catalytic converter has advantages of improved durability due to the decreased risk of damage to the catalytic converter and improved purifying performance due to the decrease in the amount of time required for catalyst activation.
However, since the aforementioned muffler having the built-in catalytic converter is manufactured and mounted to a vehicle by welding, the thickness of the components is increased. Further, since the muffler must be made of high-quality materials to be able to guarantee the muffler for as long as the catalytic unit, the weight and production cost are increased excessively. Therefore, there is a high demand for an integrated catalytic muffler structure, in which a catalytic converter is integrally coupled to a muffler to minimize the weight (e.g., thickness) and increase in production cost, thereby making it possible to more efficiently produce vehicles.